Is it more than it appears?

I was at work today when I finally calmed down from last night, and started wondering if I have developed something that is more than just depression. I’ve had depression since I was ten or something, and suicidal tendencies since I was thirteen or thereabouts – but things have changed lately. I’ve become far more angry and violent < which is a very bad thing for me. Almost completely void of emotions, and don’t seem to care even the slightest for others, (and normally I'm the one people will ask for advice or comfort if needed.) I cannot concentrate on one thought for more than a few seconds; my mind is racing through so many violent/suicidal/hateful thoughts. I’m not kind to anybody, in fact I’m the biggest jerk I could possibly be, and I’m snapping at people a lot, a lot. My random urges to do evidently wrong and cruel things are increasing, I’m taking part in self mutilation again, and along side all this, my suicidal intensions are rising. Is this just intensifying depression? I’m leaning away from the idea, because I didn’t think it could get much worse. But the odd thing is, it all comes and goes. Right now I feel mostly fine, but last night I was feeling horrible. I was a complete and utter asshole in every way, (and even threw two of my friends violently to the ground a few times <-- play fighting gone wrong). The most common thought I have right now is I should end it before I become a serious threat/danger to others.

I was better for almost two or three months, and now I’m back full throttle. This cycle repeats itself over and over again over the years. It’s like there’s a hole with layers of glass in it, every time I try and climb out of the hole I fall back down and break another layer of glass landing deeper in this hole than I was before. (I wonder how many layers of glass I have left?)

Sorry, this one was a bit lengthy. Sorry for another thread, but I’m at a total loss! I don’t know what to do anymore. I’ve made plans for suicide, many plans, and I have all the objects needed for every one of them. I have no interest in being here, but nor do I have an interest for dying. I’d much rather stay in this world, but not feeling like this. I’ve done this once before, pushed my friends away. That didn’t end well, and I tried to end my life at that point. I failed, thankfully. I can’t go to my doctor. She makes me feel like an idiot, and doesn’t believe me anyways. All I have is you guys.